Heat management at nanoscaleis a criticalissue across many areas of science and engineering,where the size effect of thermal properties plays an important role.We measure the transient thermoreflectance signals of thi...Heat management at nanoscaleis a criticalissue across many areas of science and engineering,where the size effect of thermal properties plays an important role.We measure the transient thermoreflectance signals of thin metal films with thicknesses from 50 to 200nm by using the femtosecond laser pump and probe method,and the experimental data are combined with the parabolic two-step model to enable us to measure thermal conductivity of the thin metal films.The measurement results of Ni and Al films show that,in the thickness range from tens to hundreds of nanometer,the thermal conductivity increases with the increasing thicknesses of the films,which agrees well with the previous conclusions.展开更多
目的了解上海市浦东新区男男性行为者(men who have sex with men, MSM)规模,线下交友场所活跃地点的空间分布,行为特征、安全性行为及检测等情况。方法人群规模估计采用"多中心-捕获再捕获方式",采用核密度分析法对MSM线下...目的了解上海市浦东新区男男性行为者(men who have sex with men, MSM)规模,线下交友场所活跃地点的空间分布,行为特征、安全性行为及检测等情况。方法人群规模估计采用"多中心-捕获再捕获方式",采用核密度分析法对MSM线下活动场所进行分析及找出热点区域,采用卡方检验对性行为特征进行分析;用Logistic回归模型分析安全性行为的影响因素。结果浦东新区MSM规模估计为4 386人(95%CI:1 258~7 514);浦东新区MSM线下交友地点以西北部为主;活动地点除健身场所外,还有公园、绿地、男厕所和桑拿房等,且活动规模以小型规模为主(≤5人),占61.17%,大型规模较少(50~100人),仅占3.72%;不同年龄、婚姻状况、教育情况、性取向、近半年性行为关系类型及对象类型、是否使用助性剂,发生性行为时,是否采取保护措施方面差异有统计学意义(P<0.05)。结论利用捕获-再捕获的方法,开展活跃MSM规模估计非常重要;MSM行为及安全性行为特征、活动场所及形式较为复杂,且不同年龄段可能交友场所和形式有所不同,需线上与线下调查相结合,精准定位线下活动类型,有针对性的对高危行为及热点场所进行干预,对防控艾滋病有重大意义。展开更多
基金Supported by the National Basic Research Program of China under Grant No 2012CB933200the National Natural Science Foundation of China under Grant Nos 50876103 and 50806075.
文摘Heat management at nanoscaleis a criticalissue across many areas of science and engineering,where the size effect of thermal properties plays an important role.We measure the transient thermoreflectance signals of thin metal films with thicknesses from 50 to 200nm by using the femtosecond laser pump and probe method,and the experimental data are combined with the parabolic two-step model to enable us to measure thermal conductivity of the thin metal films.The measurement results of Ni and Al films show that,in the thickness range from tens to hundreds of nanometer,the thermal conductivity increases with the increasing thicknesses of the films,which agrees well with the previous conclusions.
文摘目的了解上海市浦东新区男男性行为者(men who have sex with men, MSM)规模,线下交友场所活跃地点的空间分布,行为特征、安全性行为及检测等情况。方法人群规模估计采用"多中心-捕获再捕获方式",采用核密度分析法对MSM线下活动场所进行分析及找出热点区域,采用卡方检验对性行为特征进行分析;用Logistic回归模型分析安全性行为的影响因素。结果浦东新区MSM规模估计为4 386人(95%CI:1 258~7 514);浦东新区MSM线下交友地点以西北部为主;活动地点除健身场所外,还有公园、绿地、男厕所和桑拿房等,且活动规模以小型规模为主(≤5人),占61.17%,大型规模较少(50~100人),仅占3.72%;不同年龄、婚姻状况、教育情况、性取向、近半年性行为关系类型及对象类型、是否使用助性剂,发生性行为时,是否采取保护措施方面差异有统计学意义(P<0.05)。结论利用捕获-再捕获的方法,开展活跃MSM规模估计非常重要;MSM行为及安全性行为特征、活动场所及形式较为复杂,且不同年龄段可能交友场所和形式有所不同,需线上与线下调查相结合,精准定位线下活动类型,有针对性的对高危行为及热点场所进行干预,对防控艾滋病有重大意义。
